National Lampoon's Homo Erectus

Set in prehistoric times, this comedy follows the exploits of the hapless Ishbo (Adam Rifkin), a philosophical caveman who yearns for more out of life than sticks, stones and raw meat. Determined to single-handedly advance the human race, Ishbo continually irritates his fellow Neanderthals with ridiculous inventions like the toothbrush, the spoon and pants.